Black matrix substrate, and color filter and liquid crystal display device using the same

ABSTRACT

A black matrix substrate is provided with a substrate, and a black pattern formed on the substrate. The black pattern includes at least metal particles in a resin pattern, which comprises resin formed in a pattern shape. The metal particles have such a particle diameter distribution that particles having particle diameters in a range of 5 nm to 50 nm are not less than 80% of the total particles. A projected area density at a conversion of 600 Å thickness of the metal particles in the black pattern, is not less than 60%. An optical density of the black matrix substrate is not less than 1.5. A color filter, which has a high contrast ratio, can be constructed by use of this black matrix substrate. Further, a liquid crystal display device, which has a good image quality, can be constructed by use of this color filter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a black matrix substrate, acolor filter using the substrate and a liquid crystal display deviceusing the substrate. More particularly, it relates to a black matrixsubstrate which has a high dimensional accuracy and a goodlight-shielding property, a color filter which has a high contrastratio, and a liquid crystal display device of excellent image quality.

2. Description of the Prior Art

Much attention has been paid recently to liquid crystal display deviceof monochromatic or full color type as a flat display device. In orderto control three primary colors in such a liquid crystal display device,there are an active matrix method and a simple matrix method, each ofwhich utilizes a color filter. The liquid crystal display device isconstructed to perform color display by using picture elements of threeprimary colors (R, G, B) and controlling the transmission of each lightof the three primary colors by electrical switching of the liquidcrystal.

This color filter is constructed by forming each colored layer, aprotection layer and a transparent electrode layer on a transparentsubstrate. In order to improve a color developing effect and a displaycontrast, there is formed a pattern (black matrix), which has alight-shielding property, at a boundary portion of each R, G, B pictureelement of the colored layer. In case of the liquid crystal displaydevice of the active matrix method type, since a thin film transistor(TFT) is employed as a switching element, it becomes necessary toinhibit leaking of photo-current due to external light. Thus, it isnecessary that the black matrix exhibit a very high light-shieldingproperty.

As black matrixes used in the above mentioned prior arts, there are ablack matrix obtained by forming a relief through photo-etching of achrome thin film formed by vapor deposition or sputtering techniqueetc., a black matrix which is formed by dyeing a hydrophilic resinrelief, a black matrix obtained by forming a relief using aphoto-sensitive resin dispersed with black pigment, a black matrixobtained by. electrodeposition of a black electrocoating paint, a blackmatrix which is formed by printing technique, and so on.

However, in case of the above-mentioned black matrix, which isrelief-formed by photo-etching the chrome thin film, although theaccuracy in dimension is high because it uses the photo-process, theproduction cost is high because it requires the vacuum film formingprocess such as the vapor deposition or sputtering process and theproduction procedure is rather complicated. Further, in this case, inorder to improve the display contrast under a strong external lightcircumstance, it becomes necessary to restrain the reflectance at theside of the observer, so that a low reflection chrome sputtering processetc. is required which further increases the production cost. On theother hand, in case of the above mentioned method of using thephoto-sensitive resist dispersed with black color dye or pigment inadvance, although the production cost can be lowered, the photo-processtends to be unstable because the photo-sensitive resist has black color.Consequently, a sufficient light-shielding property is difficult toobtain if more attention is paid to the accuracy in dimension. In thismanner, there is a problem that a high quality black matrix is difficultto obtain. Further, in case of the above mentioned black matrixformation by use of the printing technique, although the production costcan be lowered to some extent, there arises a problem in case that thehigh dimensional accuracy is required.

On the other hand, the color filter is constructed by providing acolored layer, which consists of a plurality of colored patterns,between the space of the black pattern of the black matrix substrate,and by further providing a transparent electrode on this colored layer.

The liquid crystal display device is provided with the above mentionedcolor filter, an electrode substrate formed with an electrode on asubstrate, and a liquid crystal layer, in which the transparentelectrode of the color filter and the electrode of the electrodesubstrate are opposed to each other, and the liquid crystal layer isinterposed between these electrodes.

However, in the above mentioned color filter and the liquid crystaldisplay device, since the light-shielding property and the accuracy indimension are not sufficient as aforementioned in the black matrixsubstrate used by them, it is often difficult to obtain a sufficientcontrast ratio, and there is room for improving the image qualitythereof.

SUMMARY OF THE INVENTION

It is therefore a first object of the present invention to provide ablack matrix substrate, which has a high dimensional accuracy, a highlight-shielding property, and a low reflectance, and which is suitableto form a color filter for a color sensor, a flat display device such asa liquid crystal display device, an image such as a CCD (Charge CoupledDevice), and so on.

It is a second object of the present invention to provide a color filterhaving a high contrast ratio, and a liquid crystal display device havingexcellent image quality.

According to the present invention, the above mentioned first object canbe achieved by a black matrix substrate, which is provided with: asubstrate; and a black pattern formed on the substrate,

wherein the black pattern comprises resin pattern, which is formed in apattern shape, and includes at least metal particles inside thereof,

the metal particles have such a particle diameter distribution thatparticles having particle diameters in a range of 5 nm to 50 nm are notless than 80% of the total particles,

a projected area density at a conversion of 600 Å (angstrom) thicknessof the metal particles in the black pattern, is not less than 60%, and

an optical density of the black matrix substrate is not less than 1.5.

Consequently, the black matrix substrate of the present invention has ahigh dimensional accuracy, a high light-shielding property and a lowreflectance.

According to the present invention, the above mentioned second objectcan be achieved by a color filter, which is provided with: a blackmatrix substrate comprising a substrate and a black pattern formed onthe substrate; a colored layer comprising a plurality of color patternsformed between the black pattern on the black matrix substrate; and atransparent electrode formed on the colored layer,

wherein the black pattern comprises resin pattern, which is formed in apattern shape, includes at least metal particles inside thereof,

the metal particles have such a particle diameter distribution thatparticles having particle diameters in a range of 5 nm to 50 nm are notless than 80% of the total particles,

a projected area density at a conversion of 600 Å thickness of the metalparticles in the black pattern, is not less than 60%, and

an optical density of the black matrix substrate is not less than 1.5.

Consequently, the color filter of the present invention has a highcontrast ratio.

According to the present invention, the above mentioned second objectcan also be achieved by a liquid crystal display device, which isprovided with: a color filter comprising a black matrix substratecomprising a first substrate and a black pattern formed on the firstsubstrate, a colored layer comprising a plurality of color patternsformed between the black pattern on the black matrix substrate and atransparent electrode formed on the colored layer; an electrodesubstrate comprising a second substrate and an electrode formed on thesecond substrate; and a liquid crystal layer, the transparent electrodeof the color filter and the electrode of the electrode substrate beingopposed to each other, the liquid crystal layer being disposed betweenthose electrodes,

wherein the black pattern comprises a resin pattern, which is formed ina pattern shape, and includes at least metal particles inside thereof,

the metal particles have such a particle diameter distribution thatparticles having particle diameters in a range of 5 nm to 50 nm are notless than 80% of the total particles,

a projected area density at a conversion of 600 Å thickness of the metalparticles in the black pattern, is not less than 60%, and

an optical density of the black matrix substrate is not less than 1.5.

Consequently, the liquid crystal display device of the present inventionhas a good image quality.

The nature, utility, and further features of this invention will be moreclearly apparent from the following detailed description with respect topreferred embodiments of the invention when read in conjunction with theaccompanying drawings briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing one example of an active matrixtype liquid crystal display device, which uses a color filter of thepresent invention;

FIG. 2 is a summarized sectional view of the liquid crystal displaydevice of FIG. 1;

FIG. 3 is a magnified partial sectional view of the color filter used inthe liquid crystal display device of FIG. 1;

FIG. 4 is a process diagram showing one example of a method suitablyemployed to manufacture a black matrix substrate of the presentinvention;

FIG. 5 is a summarized sectional view of the black matrix substrate ofthe present invention;

FIG. 6 is a process diagram showing another example of a method suitablyemployed to manufacture a black matrix substrate of the presentinvention;

FIG. 7 is a process diagram showing another example of a method suitablyemployed to manufacture a black matrix substrate of the presentinvention;

FIG. 8 is a diagram schematically showing a method to measure aprojected area density of a particle, in which FIG. 8A shows a conditionof slicing a detached black color pattern 14 by a width of 600 Å(angstrom) in the direction of its thickness, FIG. 8B shows thecondition of observing the sliced piece 14a from the sliced surfacedirection by use of a transmission electron microscope;

FIG. 9 is an electron microscope picture of a sliced piece, which isobtained by slicing a black pattern produced as a sample 1 of thepresent invention by a width of 600 Å in the direction of its thickness,when it is observed from the direction of the sliced surface, by use ofa transmission electron microscope;

FIG. 10 is an electron microscope picture of the sliced piece same as inFIG. 9, when it is observed under the condition of a magnification ofwhich is 5 times as high as that in FIG. 9;

FIG. 11 is an electron microscope picture of a sliced piece, which isobtained by slicing a black pattern produced as a sample 3 of thepresent invention by a width of 600 Å in the direction of its thickness,when it is observed from the direction of the sliced surface, by use ofa transmission electron microscope;

FIG. 12 is an electron microscope picture of the sliced piece same as inFIG. 11, when it is observed under the condition of a magnification ofwhich is 5 times as high as that in FIG. 11;

FIG. 13 is an electron microscope picture of a sliced piece, which isobtained by slicing a black pattern produced as a comparison sample by awidth of 600 Å in the direction of its thickness, when it is observedfrom the direction of the sliced surface, by use of a transmissionelectron microscope; and

FIG. 14 is an electron microscope picture of the sliced piece same as inFIG. 13, when it is observed under the condition of a magnification ofwhich is 5 times as high as that in FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the accompanying drawings, embodiments of the presentinvention will be now explained.

FIG. 1 is a perspective view showing one example of an active matrixtype liquid crystal display device (LCD), which uses a black matrixsubstrate of the present invention. FIG. 2 is a summarized sectionalview of the liquid crystal display device of FIG. 1.

In FIG. 1 and FIG. 2, a LCD 1 is constructed as follows. Namely, a colorfilter 10 and a transparent glass substrate 20 are opposed to each otherthrough a seal member 30. A liquid crystal layer 40, which has athickness of about 5 to 10 μm and which comprises twisted nematic (TN)liquid crystal, is disposed between them. Light polarization plates 50and 51, are disposed at the outer sides of the color filter 10 and thetransparent glass substrate 20.

FIG. 3 is a magnified partial sectional view of the color filter 10.

In FIG. 3, the color filter 10 is provided with a black matrix substrate12, which is constructed by forming black pattern (black relief or blackmatrix) 14 on a transparent substrate 13, a colored layer 16, which isdisposed between the spaces of the black matrix 14 of the black matrixsubstrate 12, a protection layer 18, which is disposed to cover theblack matrix 14 and the colored layer 16, and a transparent electrode19. The color filter 10 is disposed such that the transparent electrode19 is positioned at the side of the liquid crystal layer 40. The coloredlayer 16 has red pattern 16R, green pattern 16G and blue pattern 16B,which are arranged in a mosaic arrangement as shown in FIG. 1. Thearrangement of the colored pattern is not limited to this. Instead, atriangle arrangement, a stripe arrangement etc. may be employed here.

On the other hand, on the transparent glass substrate 20, displayelectrodes 22 are disposed in correspondence with each colored pattern16R, 16G, 16B. Each of the display electrodes 22 has a thin filmtransistor (TFT) 24. Scanning lines (gate electrode base lines) 26a anddata lines 26b are disposed between the display electrodes 22 incorrespondence with the black matrix 14.

In the LCD 1, each of the colored patterns 16R, 16G and 16B constructs apicture element, so that the liquid crystal layer 40 is operated as ashutter by turning ON/OFF the display electrode corresponding to eachpicture element under the condition that illumination light isirradiated from the side of the polarization plate 51, and the colordisplay is able to work by transmitting the light through each pictureelement of the display patterns 16R, 16G and 16B.

The black matrix substrate 12 constructing the color filter 10, isprovided with a substrate 13 and the black pattern 14, which is formedon the substrate 13 and includes at least metal particles therein, asshown in FIG. 5.

As the substrate 13, a transparent substrate or a substrate having areflection portion, may be used. As the transparent substrate, rigidmaterial having no flexibility such as quartz glass, borosilicate glass,soda lime glass, a low expansion glass etc., may be used. Alternatively,material having flexibility, such as transparent resin film, opticalresin plate etc., may be used. Among those, 7059 glass made by CorningCo., is especially suitable for the color filter of the active matrixLCD, since it is a material having a low thermal expansion coefficient,thus giving a good stabilization property in dimension and a goodoperatability in a high temperature heat treatment, and since it isnon-alkaline glass which does not include an alkali component. For theusage of the reflection projecting type etc., a metal reflection filmmay be formed on one side of the transparent substrate, or a metalreflection film, may be used for the display electrode of the thin filmtransistor or the active matrix on the silicon substrate. If a substratehaving the reflection portion is utilized, it becomes a black matrixsubstrate for a color filter of reflection type, which is suitable fordisplay modes of the reflection projection mode, the Guest Host mode andthe scattering mode.

The black pattern 14 has resin formed in a predetermined pattern shape(hereinbelow, it is referred to as "resin pattern"), and metal particlesincluded in this resin. The black pattern 14 is formed by depositing themetal particles in the resin pattern containing a catalyst byelectroless plating by use of reducing agent having a capability ofreducing metal ion included in the electroless plating solution. As theresin used for the resin pattern, the resin, which can be formed by aprinting method or photolithography method, can be adapted. As the resinused in the printing method, there are various known gravure inks etc.with respect to the engrave plate offset printing, for example. In thiscase, the catalyst component, which will be explained later on, may beincluded in the ink in advance, or the catalyst component may be soakedin the ion condition in the afterprocess, so that the catalytic propertyis given by reducing afterward. As for the resin used in thephotolithography method, it will be explained afterward together withthe process.

The metal particles included in the black pattern 14 preferably havesuch a particle diameter distribution that particles having particlediameters in a range of 5 nm to 50 nm are not less than 80% of the totalparticles. More preferably the metal particles have such a particlediameter distribution that particles having particle diameters in arange of 10 nm to 30 nm, most preferably 10 nm to 20 nm, are not lessthan 80% of the total particles, in order to make the optical densityhigh while keeping the reflectance low. If it does not have this kind ofparticle diameter distribution, and if there are increased particleswhich diameters are more than 50 nm, the metal particles not only havethe reflecting property but also form a continuous film on the filmsurface, thus resulting in a problem that the film surface is covered bythe continuous film and the plating reaction in the resin is disturbed.On the other hand, if it does not have this kind of particle diameterdistribution, and if there are increased particles which diameters areless than 5 nm, there is caused a problem results that the opticaldensity (more than 1.5) which is required as a black matrix, cannot beobtained. In the present invention, the particle diameter means a value,which is obtained by measuring firstly sample diameters of 100 samples,for example, by means of TEM profile photographing of a black matrixsliced piece, and then statistically processing the measured result.

The projection area density, which is obtained by measuring the ratio ofshade area made by the metal particles to the whole area in the blackmatrix pattern 14, is preferably not less than 60%, and more preferablynot less than 80%, and it is necessary that the optical density of theblack pattern is not less than 1.5. If the protected area density at aconversion of 600 Å thickness of the particles is less than 60%, even ifthe particle diameter is within the above mentioned prescription of thepresent invention, the necessary optical density cannot be obtained. Theoptical density is also related with the thickness of the film of theblack pattern 14. Therefore, this thickness is set so that the opticaldensity becomes more than 1.5. If the optical density is less than 1.5,the light-shielding property as the black matrix becomes insufficient.The projected area density at a conversion of 600 Å thickness of theparticles is, as shown in FIG. 8, obtained by performing asuper-microtome with respect to the black pattern 14 in the direction ofits thickness, slicing it by a width of 600 Å (FIG. 8A), and observingthis sliced piece 14a from the direction of the sliced surface by meansof a transmission electron microscope (FIG. 8B). As one concrete exampleof measuring method, the thickness of the sliced piece is measured by amultiplex differential interference type microscope etc., and one closeto 600 Å is selected to be used. It is difficult to slice it just by 600Å. Therefore, assuming that the thickness of the sliced piece close to600 Å is t (Å) and that the measured value d (%) is obtained as theprojected area density at this time, its conversion to the projectedarea density D (%) of 600 Å thickness is calculated by the followingformula. ##EQU1##

The particle diameter of the metal particle is varied due to the factorsof, for example, (1) the plating time, (2) the plating bath temperatureor the pH of the plating solution in the process of plating reaction,(3) the stirring vibration motion of the plating solution (4) theconcentration of the catalyst treatment solution at the time of applyingthe catalyst into resin pattern and the catalyst treatment time thereofand so on, in the manufacturing method of the black matrix substrate. Atleast one of the reflectance from the substrate side of the blackpattern 14 and the reflectance from the surface side of the blackpattern, is preferably not more than 30%, and more preferably not morethan 15%. If it exceeds 30%, the reflection due to the external lightdisturbs the image quality, resulting in an insufficient displaycontrast.

One example of the method of manufacturing the black matrix substrate 12of the present invention, will be explained hereinbelow with referringto FIG. 4. The resin pattern is formed by means of the photolithographytechnique, here. Firstly, a photo-sensitive resist layer 3, which has athickness of about 0.1 to 5.0 μm, is formed by coating photo-sensitiveresist, which includes hydrophilic resin, on the substrate 13 (FIG. 4A).Nextly, the photo-sensitive resist layer 3 is light-exposed through aphotomask 9 for the black matrix (FIG. 4B). Then, the photo-sensitiveresist layer 3 after light-exposure, is developed, so that the reliefimage 4 (resin pattern) having the pattern for the black matrix, isobtained (FIG. 4C). Nextly, after applying a heat treatment (70° to 200°C., about 5 to 60 minutes) to the transparent substrate 13, the reliefimage 4 is soaked in an aqueous solution of the metal compound servingas a catalyst for the electroless plating, so that the relief 5including catalyst (resin pattern including catalyst), is obtained afterwashing by water (FIG. 4D). Then, the black pattern (black relief) 14 isobtained by contacting the relief 5 including catalyst on thetransparent substrate 13 with the electroless plating solution, andfurther, a film-hardening treatment by applying heat or applying filmhardening agent, is applied to this black pattern to produce the blackmatrix substrate 12 (FIG. 4E). The heat process may be applied afterforming the relief including catalyst.

In the example shown in FIG. 6, the photo-sensitive resist layer 6,which has a thickness of about 0.1 to 5.0 μm, is formed on the substrate13 by coating photo-sensitive resist including hydrophilic resin andaqueous solution of metal compound serving as a catalyst for theelectroless plating (FIG. 6A). Nextly, the photo-sensitive resist layer6 is light-exposed through the photomask 9 for the black matrix (FIG.6B). Then, the photo-sensitive resist layer 6 is developed and driedafter light exposure, so that a relief image (resin pattern includingcatalyst) 7, which has a pattern for the black matrix is obtained (FIG.6C). The relief image 7 in this case, is different from the relief image4 shown in FIG. 4, and is a relief including catalyst (resin patternincluding catalyst), which includes metal compound to be the catalystfor the electroless plating.

In order to produce the black pattern (black matrix) 14 by use of therelief image 7 constructed as above, firstly, heat treatment (70° to200° C., about 5 to 60 minutes ) is applied to the relief image 7, andthen the relief image (relief including catalyst) 7 on the substrate 13is contacted with the electroless plating solution, so that the metalparticles are deposited in the relief to be black-colored, and finallythe black pattern (black matrix) 14 is formed (FIG. 6D). In this case,the film hardening process by applying heat or film hardening agent maybe also performed to the black matrix.

Further, in the example shown in FIG. 7, firstly, the photo-sensitiveresist layer 8, which has a thickness of about 0.1 to 5.0 μm, preferablyabout 0.1 to 2.0 μm, is formed by coating photo-sensitive resistincluding hydrophilic resin, compound having diazo group or azide groupand the metal compound serving as a catalyst for the electrolessplating, on the transparent substrate 13 and drying it (FIG. 7A). Here,it is known that the compound having the diazo group or the azide group,is effective in restraining the plating in the process of electrolessplating, and that when the resist, which includes the hydropdhilic resinand the compound serving as a catalyst for the electroless plating, issubjected to pattern exposure and then brought into contact withelectroless plating solution, metal particles are formed in the resistby the electroless plating to form a light-shielding layer (JapanesePatent Application Laid Open No. Sho. 57-104928, 57-104929). Nextly, arelief image 8' of the present invention is formed by light-exposing thephoto-sensitive resist layer 8 through the photomask 9 for the blackmatrix (FIG. 7B). Namely, this relief image 8' is to be a reliefincluding catalyst, which includes the metal compound serving as acatalyst for the electroless plating, and in which the above mentionedplating restraining effect by the diazo group or the azide group isreleased in the pattern shape of the black matrix by the light-exposure.

In order to produce the black matrix 14 by use of the relief image 8'constructed as above, the substrate 13 is contacted with the electrolessplating solution, so that the metal particles of the electroless platingare disposed at the light-exposed portions to be black-colored, so thatthe black matrix 14 is finally obtained (FIG. 7C).

The portions, which are not light-exposed, may be removed by developingas shown in FIG. 7D.

In the above mentioned examples of the production method of the blackmatrix substrate, a common feature is that the electroless platingprocess is not performed by use of plating bath at a temperature ofabout 70° C. to 90° C. as in the conventional electroless plating, butis performed by use of that at a temperature of about 20° C. to 40° C.under the existence of the metal compound serving as a catalyst forelectroless plating, and that the reduction of the metal salt, which isincluded in the electroless plating solution, is performed very slowlycompared with the conventional electroless plating, by use of a reducingagent capable of reducing the metal compound and the metal salt. So, themetal particles are slowly deposited to grow in the resist (resin) sothat the metal particles are homogeneously deposited in the blackpattern (light shading layer).

Therefore, the black pattern includes the metal particles and, undersome circumstances, the metal salt to be reduced. The black pattern alsoincludes the metal compound to be the electrolessly plated and, undersome circumstances, the metal generated by reducing this metal compound.The black pattern further includes the reducing agent.

The resin pattern of the black pattern 14 is formed by use of naturalprotein, protein which is made from natural protein with artificialtreatment, hydrophilic natural resin, hydrophilic synthetic resin, etc.Among these, a photo-sensitive resist is especially suitable for theresin pattern since it is capable of forming a relief pattern with highdimentional accuracy.

As the photo-sensitive resist, there are, for example, natural proteinsuch as gelatin, casein, glue, egg white albumin, etc.,carboxymethyl-cellulose, polyvinyl alcohol, polyacrylic acid,polyacrylamide, polyvinyl pyrrolidone, polyethylene oxide, and maleicanhydride copolymer. As another example thereof, there is material towhich the photo-sensitivity is given by adding material which has aphoto-sensitive group of photo-hardening type, such as diazoniumcompound having diazo group, diazo resin which is the reaction productof paraformaldehyde, azide compound having azide group, cinnamic acidcondensed resin which is produced by condensing cinnamic acid topolyvinyl alcohol, resin using stilbazolium salt, heavy chromateammonium etc., with respect to simple or mixed substances of hydrophilicresin such as the above mentioned resin which is modified by carboxylicacid or sulfonic acid. Inorganic material such as ceramics or porousalumina etc., may be added to the photo-sensitive resist. This inorganicmaterial may be included in the photo-sensitive resist at a range of 0.1to 10 wt %. The photo-sensitive group is not limited to the abovementioned photo-hardening type photo-sensitive group. In this manner, bymaking the photo-sensitive resist include the hydrophilic resin, whenthe relief 5 including catalyst contacts the electroless platingsolution as aforementioned, the electroless plating solution can easilypermeate the relief 5 including catalyst, so that the metal particlescan be deposited to grow homogeneously, in the relief 5 includingcatalyst.

As the hydrophilic polyvinyl alcohol resin, there are modified polyvinylalcohol and non-modified polyvinyl alcohol. Further, as the abovementioned modified polyvinyl alcohol, there is polyvinyl alcohol whichis modified by sulfonic acid group, acetoacetyl group, cationic group,acrylicamide group, or carboxyl group, for example. The saponificationvalue of these hydrophilic polyvinyl alcohol resin is preferably 86 to99, and the average degree of polymerization thereof is preferably 500to 1700.

Here, it is important to have a good depositing property of the metalparticles into the resin pattern including the catalyst component asmentioned before, in order to obtain the high optical density property,the low reflectance property etc., as the demanded properties for theblack matrix. This depositing property of the metal particles isconsidered to have a strong relationship with the osmosis of theelectroless plating solution in the resin pattern including thecatalyst. Therefore, the structural property of the polyvinyl alcoholresin included in the photo-sensitive resist, becomes important. Ingeneral, it is known that the swelling property of a coated film of apolyvinyl alcohol film in aqueous solution, depends on itscrystallization property. Thus, it is considered that the osmosis of theelectroless plating solution depends on the crystallization property ofthe polyvinyl alcohol in the photo-sensitive resist.

In the present invention, in view of the above discussion, the X rayscattering intensity value, when the crystallization of the polyvinylalcohol in the resin pattern before forming the black pattern isevaluated by the scattering intensity value of the X ray diffractionmethod, is preferably in a range of 200 to 580 cps/μm, and is morepreferably in a range of 300 to 400 cps/μm. If this scattering intensityvalue exceeds 580 cps/μm, the depositing property of the metal particlesinto the resin pattern is degraded, so that the black matrix having ahigh optical density (about not less than 3) cannot be obtained. On theother hand, if this scattering intensity value is less than 200 cps/μm,there is caused a problem that the resin pattern including the catalyst(relief including catalyst) is dissolved in the electroless platingsolution.

In order to set the X ray scattering intensity value of the polyvinylalcohol in the resin pattern before forming the black pattern to theaforementioned preferable range, for example, the X ray scatteringintensity value of the polyvinyl alcohol in the photo-sensitive resist,may be set to the aforementioned preferable range, or the X rayscattering intensity value of the polyvinyl alcohol to form the resinpattern including the catalyst may be set to the aforementionedpreferable range by controlling the condition of the heat treatmentprocess of the resin pattern including the catalyst in the process shownin FIG. 4, for example.

In this manner, by setting the X ray scattering intensity value of thepolyvinyl alcohol in the resin pattern before forming the black pattern,to a value within the aforementioned preferable range, when the reliefincluding catalyst contacts with the electroless plating solution, theelectroless plating solution can easily permeate into the reliefincluding catalyst, so that the metal particles deposit in the reliefincluding catalyst homogeneously and speedily. Thereby, the formed blackmatrix 14 has a high optical density and a low reflectance while theaccuracy in dimension is high, and the problem of the reflection by themetal layer in the black matrix consisting of a chromium film in theaforementioned prior art, can be solved.

As the metal compound used as the catalyst for the electroless platingused in the present invention, there are water soluble salts and complexcompounds of chloride, sulfate, nitrate etc. of palladium (Pd), gold(Au), silver (Ag), tin (Sn), zinc (Zn), platinum (Pt), copper (Cu) forexample. Especially, in the present invention, an activator solution forelectroless plating, which is sold in the market as an aqueous solution,can be used as it is, or after diluting it. When including this kind ofmetal compound into the photo-sensitive resist as mentioned above, it ispreferable that it is included by about 0.01 to 5 wt % at a conversionof metal ion.

As the electroless plating solution used in the present invention, thereis electroless plating solution including: reducing agent such ashypophosphrous acid, sodium hypophosphite, boron sodium hydride,N-dimethylamine borane, borazine derivative, hydrazine and formalin;water soluble heavy metal salts, which are to be reduced (which formsmetal ion in the plating solution), of metals such as nickel (Ni),cobalt (Co), iron (Fe), copper (Cu), chromium (Cr), palladium (Pd), gold(Au), platinum (Pt), tin (Sn) and zinc (Zn); basic compounds to improvethe plating speed and the reducing effect etc. such as sodium hydroxide,potassium hydroxide and ammonium hydroxide; pH adjusting agents such asinorganic acid and organic acid; buffer agents represent by alkalinesalts of oxocarboxylic acid such as sodium citrate and sodium acetate,boric acid, carbonic acid, organic acid and inorganic acid; andcomplexing agents, represent by organic carboxylic acids such as citricacid, trisodium citrate, hydrogen diammonium citrate, tartaric acid,sodium tartrate, glycollic acid, sodium succinate, sodium malonate,glycine, Rochelle salt, malic acid, ethylenediamine, diethyletriamine,triethylene tetramine, and the salts of those acids, to aim atstabilizing the heavy metal ion, reaction promoting agent, stablilizingagent, surface activate agent and so on. The concentration of thereducing agent is preferably 0.03 to 0.07 mol/l, the concentration ofthe complexing agent is preferably 0.1 to 1.0 mol/l, and theconcentration of the metal salt is preferably 0.1 to 0.3 mol/l in theelectroless plating solution, respectively.

The pH value of the electroless plating solution is preferably 6 to 9,and the temperature of the plating solution is preferably 20° to 40° C.,to control the reaction rate in the electroless plating.

More than one kind of electroless plating liquid may be used together.For example, firstly, an electroless plating solution including borontype reducing agent such as boron sodium hydride which tends to form anucleus (for example, a nucleus of palladium in case of using palladiumas the metal compound to be the catalyst for the electroless plating),is used, and nextly, an electroless plating solution includinghypophoshite type reducing agent having a high metal depositing rate, isused.

In the above various kinds of reducing agents, the boron type reducingagent can be used preferably, since it is superior in the capability ofreducing both of the metal compound to be the catalyst for theelectroless plating, and the metal salt to be reduced, at the same time.

The formation of the colored layer 16, which comprises the red pattern16R, the green pattern 16g and the blue pattern 16B between the blackmatrix 14 of the above mentioned black matrix substrate 12, can beperformed by various known methods, such as the photo-resist coloringmethod, the dispersing method to perform patterning by photolithographyafter coating the photo-sensitive resin dispersed with pigment inadvance, the printing method, e.g. offset printing, and theelectrodepositing method.

The protection layer 18 may be provided such that it covers the blackmatrix 14 and the colored layer 16 of the color filter 10, so as tosmooth the surface of the color filter 10, improve the reliability ofthe color filter 10, and prevent the contamination to the liquid crystallayer 40. The protection layer 18 may be formed by use of transparentresin such as acrylic resin, polyurethane resin, polyester resin, epoxyresin and polyimide resin, wherein especially the resin ofthermo-setting or photo-setting type, can be preferably used.Alternatively, it may be formed by use of transparent inorganic compoundsuch as silicon dioxide. The thickness of the protection layer 18 ispreferably about 0.5 to 50 μm.

As the transparent common electrode 19, indium tin oxide (ITO) film canbe used, for example. This ITO film can be formed by various knownmethods, such as the vapor deposition method and the sputtering method.The thickness of this ITO film is preferably about 200 to 2000 Å.

Nextly, the present invention will be explained in more detail, byshowing its experimental examples.

Experimental Example 1 Production of Sample 1 of the Present Invention

As the transparent substrate, a plasma-treated polyester film (LumirrorT/100, made by Toray Industries, Inc.) with thickness of about 100 μm,which is attached onto a glass substrate, is prepared. Thephoto-sensitive resist having the composition listed below, is coated onthis polyester film of the glass substrate, by a spinner coating method(1500 r.p.m.), to have a thickness of about 0.6 μm. After that, it isdried at a temperature of about 70° C. for about 10 minutes, so that thephoto-sensitive resist layer is formed.

Composition of the Photo-Sensitive Resist

polyvinyl alcohol (Gohsenal T-330, made by Nippon Synthtic ChemicalIndustry Co., Ltd.) 4.47% aqueous solution . . . 100 wt. parts

diazo resin (D-011, made by Shinco Giken Co.) 4.47% aqueous solution . .. 5.71 wt. parts

Nextly, the transparent film, which has the photo-sensitive resistlayer, is removed from the glass, and after that, this film is exposedby light through the photomask for forming the black matrix (negativetype, line width=20 μm). As the light source, a super high pressuremercury lamp 2 Kw is used, to expose for 2 seconds. After that, by useof water at room temperature, the spray development is performed, andthen, air drying is performed. Nextly, a heat treatment is applied tothis transparent film at a temperature of about 100° C. for about 30minutes, so that a relief having a thickness of about 20 μm for theblack matrix, is formed.

Nextly, this transparent film is soaked in palladium chloride aqueoussolution (5 times diluted solution of Red Sumer, made by Kanigen Co.)for 2 minutes. After water-washing and dewatering, it is soaked innickel plating solution including dimethyl amine borane as reducingagent (nickel plating solution Top Chem Alloy B-1, made by Okunochemical Industries Co.,Ltd.) at a temperature of about 30° C. for about4 minutes, and undergoes water-washing and drying, so that the lightshading layer (black matrix) is formed, to obtain the black matrixsubstrate of the present invention.

The black pattern of this sample 1 is sliced by a width of 600 Å in thedirection of its thickness. The sliced piece is observed by atransmission electron microscope (H-8100, made by Hitachi Ltd.) from thedirection of the sliced surface, and photographing is conducted underthe condition listed below. The electron microscope photograph is shownin FIG. 9.

Photographing Condition

acceleration electric voltage . . . 200 KV

beam electric current . . . 10 μm

converging variable diaphragm . . . 80 μm

objective variable diaphragm . . . 40 μm direct magnification(photographing magnification) . . . 20 K times

enlarging magnification (final magnification) . . . 100 K times

Further, with respect to the above mentioned sliced piece of the sample1, photographing is conducted under the condition listed below. Theelectron microscope photograph is shown in FIG. 10.

Photographing Condition

acceleration electric voltage . . . 200 KV

beam electric current . . . 10 μm

converging variable diaphragm . . . 80 μm

objective variable diaphragm . . . 40 μm

direct magnification (photographing magnification) . . . 100 K times

enlarging magnification (final magnification) . . . 500 K times

Production of Sample 2 of the Present Invention

A sample 2 of the present invention is produced in the same manner asthe above explained sample 1 of the present invention except forchanging the plating time from 4 minutes to 10 minutes.

Production of Sample 3 of the Present Invention

A sample 3 of the present invention is produced in the same manner asthe above explained sample 1 of the present invention except forchanging the plating time from 4 minutes to 15 minutes.

The black pattern of this sample 3 is sliced by a width of 600 Å in thedirection of its thickness. The sliced piece is observed by atransmission electron microscope from the direction of the slicedsurface, and photographing is conducted under the condition listedbelow. The electron microscope photograph is shown in FIG. 11.

Photographing Condition

acceleration electric voltage . . . 200 KV

beam electric current . . . 10 μm

converging variable diaphragm . . . 80 μm

objective variable diaphragm . . . 40 μm

direct magnification (photographing magnification) . . . 20 K times

enlarging magnification (final magnification) . . . 100 K times

Further, with respect to the above mentioned sliced piece of the sample3, photographing is conducted under the condition listed below. Theelectron microscope photograph is shown in FIG. 12.

Photographing Condition

acceleration electric voltage . . . 200 KV

beam electric current . . . 10 μm

converging variable diaphragm . . . 80 μm

objective variable diaphragm . . . 40 μm

direct magnification (photographing magnification) . . . 100 K times

enlarging magnification (final magnification) . . . 500 K times

Production of Sample 4 of the Present Invention

A sample 4 of the present invention is produced as follows: Namely,until the relief forming process, the same processes to produce theaforementioned sample 1 are performed. Then, it is soaked in palladiumchloride aqueous solution, which has high concentration available forcatalyst (50 times diluted solution of Red Sumer, made by Kanigen Co.),as the catalyst activating solution, for 2 minutes. Then, after waterwashing and dewatering, it is soaked in nickel plating solution at aroom temperature, which includes dimethyl amine borane as a reducingagent (nickel plating solution Top Chemi Alloy B-1, made by OkunoChemical Industries Co.,Ltd.), for 9 minutes. Then, after water washingand drying, the black pattern (black matrix) is formed, so that theblack matrix substrate is finally obtained.

Production of a Sample 5 of the Present Invention

A sample 5 of the present invention is produced in the same manner asthe above explained sample 4 of the present invention except forchanging the plating time from 9 minutes to 35 minutes.

Production of a Comparison Sample 1

A comparison sample 1 is produced in the same manner as the aboveexplained sample 1 of the present invention except for changing theplating time from 4 minutes into 1 minute.

The black pattern of this comparison sample 1 is sliced by a width of600 Å in the direction of its thickness. The sliced piece is observed bya transmission electron microscope from the direction of the slicedsurface, and photographing is conducted under the condition listedbelow. The electron microscope photograph is shown in FIG. 13.

Photographing Condition

acceleration electric voltage . . . 200 KV

beam electric current . . . 10 μm

converging variable diaphragm . . . 80 μm

objective variable diaphragm . . . 40 μm

direct magnification (photographing magnification) . . . 20 K times

enlarging magnification (final magnification) . . . 100 K times

Further, with respect to the above mentioned sliced piece of thecomparison sample 1, photographing is conducted under the conditionlisted below. The electron microscope photograph is shown in FIG. 14.

Photographing Condition

acceleration electric voltage . . . 200 KV

beam electric current . . . 10 μm

converging variable diaphragm . . . 80 μm

objective variable diaphragm . . . 40 μm

direct magnification (photographing magnification) . . . 100 K times

enlarging magnification (final magnification) . . . 500 K times

Production of Comparison Sample 2

A comparison sample 2 is produced in the same manner as theaforementioned sample 1 of the present invention except for changing theplating time from 4 minutes to 2 minutes.

Production of Comparison Sample 3

A comparison sample 3 is produced in the same manner as theaforementioned sample 4 of the present invention except for changing theplating time from 9 minutes to 3 minutes.

Production of Comparison Sample 4

A comparison sample 4 is produced in the same manner as theaforementioned sample 4 of the present invention except changing theplating time from 9 minutes to 6 minutes.

With respect to those 9 samples (the samples 1 to 5 of the presentinvention, the comparison samples 1 to 4), the particle diameters andthe projected area densities of the nickel fine particles deposited inthe black pattern (light shading layer), are measured by a transmissionelectron microscope (H8100, made by Hitachi Ltd.).

Further, the optical densities (OD) and the reflectances (R) of theblack matrixes at the wavelength of 555 nm, are measured by amicroscopectrophotometry device (AH2-SRK/STK, made by Olympus KogakuKogyo Co.), with respect to the regular reflected light of the lightwhich is incident substantially perpendicularly to the substrate. Theoptical density (OD) of the black matrix is calculated by the followingformula: OD=-log (T/100), with respect to the transmittance T (%) whichis the highest value within the visible region of 400 to 700 nm measuredby the above mentioned device by use of a standard value under acondition that the transparent substrate is used as a reference (100%transmittance) and the light is perfectly shut off as a background (0%transmittance). The reflectance is measured by using, as a standard, thecase that there is no reflecting object at all with an aluminum vapordeposited plate as a background as a reference. As the reflectance, twokinds of reflectances are measured, namely, one reflectance in case thatthe light is irradiated from the substrate side (observer side) of theblack pattern 14 and another reflectance in case that the light isirradiated from the side of the surface (film surface) of the blackpattern 14.

The measured results are shown in Table 1. Table 1, the range of theoptical density is set as OD≧3, since the transmittance is not more than0.1% if the optical density is not less than 3, and since there is nomeaningful difference of the value not more than 0.1%.

As understood from the results shown in Table 1, in each of the samples1 to 5 of the present invention, the nickel particles which particlediameters are in the range of 5 to 50 nm, are 80% of the totalparticles, and the projected area density of the particles is not lessthan 60%. Therefore, the reflectance at the side of the observer (theopposite side of the film surface) is drastically reduced compared withthe conventional metal chromium (the reflectance is not less than 60%),and the necessary optical density (not less than 1.5) as the blackpattern of the light shading layer, can be sufficiently obtained, sothat it is excellent as a black matrix substrate. Especially, the sample1 of the present invention is superior in the reflectance from the filmsurface side. On the contrary, in each of the comparison samples 1 and3, although the average particle diameter of the nickel particles isabove 5 nm, the nickel particles, which particle diameters are less than5 nm, are not less than 20% of the total particles and the projectedarea density of the particles is not more than 20%. Therefore, althoughthe reflectance is rather low, the necessary optical density as theblack pattern (black matrix) of the light shading layer, which is thefundamental function thereof, cannot be obtained, so that it is notsufficient as a black matrix substrate (this fact can be well confirmedby visual inspection). Further, in each of the comparison samples 2 and4, the average particle diameter of the nickel particles is 9.3 nm, and14.1 nm respectively, and the particles which have the particlediameters in the range of 5 to 50 nm, are not less than 80% of the totalparticles. Thus, although as for these, the values are within theprescription of the present invention, the projected area density of theparticles is less than 60% (57.3%, 54.0%, respectively). Therefore, thesufficient optical density cannot be obtained by them, and thus, in thesame manner as the comparison samples 1 and 3, it is not sufficient asthe black matrix substrate.

Experimental Example 2

Nextly, under the same conditions as sample 1 of the present invention,the black pattern is formed on a glass substrate. By use of this blackmatrix substrate, a color filter is produced in the following procedure.

Namely, ink compositions S-1, S-2 and S-3 as listed below, are printedbetween the black matrix on the black matrix substrate in this order byan engraving offset printing by use of a plate, which has an engravedportion in a stripe shape having a plate depth of 6 μm and a width of110 μm, and a silicon blanket, so that stripe patterns of blue, greenand red are formed by printing respectively, each of which has a widthof 110 μm. After that, by heating the above mentioned substrate at atemperature of about 200° C. for about 30 minutes, thermo-setting of theink compositions are performed, so that the colored layer having a filmthickness of about 2 to 3 μm, is obtained.

Composition of Varnish

polyesteracrylate resin (Alonix M-7100, made by Toagosei chemicalIndustry Co., Ltd.) . . . 70 wt. parts

diallyl phthalate prepolymer . . . 30 wt. parts

Composition of Ink Composition S-1

varnish . . . 100 wt. parts

pigment (Lionol blue ES) (C.I. Pigment Blue 15:6, made by Toyo InkManufacturing Co.) . . . 15.5 wt. parts

pigment (Lionogen violet RL) (C.I. Pigment Violet 23, made by Toyo inkManufacturing Co.) . . . 4 wt. parts

Composition of Ink Composition S-2

varnish . . . 100 wt. parts

pigment (Lionol green 2YS) (C.I. Pigment Green 36, made by Toyo inkManufacturing Co.) . . . 22 wt. parts

pigment (Seika fast yellow 2700) (C.I. Pigment Yellow 83, made byDainichiseika Kogyo K.K.) . . . 7.5 wt. parts

Composition of Ink Composition S-3

varnish . . . 100 wt. parts

pigment (Chromophthal red A3B) (C.I. Pigment Red 177, by Chiba-GaigyLtd.) . . . 32 wt. parts

pigment (Seika fast yellow 2700) (C.I. Pigment Yellow 83, made byDainichiseika kogyo K.K.) . . . 8 wt. parts

Nextly, the protection layer and the transparent layer are formed asaforementioned, so that the color filter is obtained.

Namely, the protection layer (film thickness=2.0 μm) is formed on theabove mentioned colored layer by coating the coating solution listedbelow, by use of spinner coating method (rotation speed=1500 r.p.m.).

Composition of the Coating Solution to form the Protection Layer

photo-hardening type acrylate oligomer (o-cresol novolak epoxiacrylate(molecular weight 1500 to 2000)) . . . 35 wt. parts

cresol novolak type epoxy resin . . . 15 wt. parts

mulfunctional polymericmonomer (dipentaerythitol hexaacrylate (DPHA madeby Nippon Kayaku Co. Ltd.)) . . . 50 wt. parts

polymerization initiating agent (Irgacure, made by Chiba-Gaigy Ltd.) . .. 2 wt. parts

epoxy hardening agent (UVE 1014, made by General Electric Co.) . . . 2wt. parts

2-methoxyetanol acetate . . . 200 wt. parts

With respect to this coating film, a light exposure for the wholesurface, with a light exposure amount of 150 mJ/cm², is performed by useof a proximity exposing device made by Dainihon screen Co. After that,the substrate is soaked in 1, 1, 2, 2-tetrachloroethane at roomtemperature for 1 minute, so that only the uncured portion of thecoating film is removed, and the protection film is formed.

Further, on this protection film, an indium tin oxide (ITO) film isformed to be a transparent electrode, which has a thickness of 0.4 μm,by means of the sputtering method, so that the color filter is obtained.

LCD panels are produced by use of the color filter constructed asmentioned above, and by use of a TFT substrate formed by a conventionalknown method.

Here, amorphous silicon is used for a semiconductor layer of this TFTsubstrate, and the polarization plates of the LCD are attached such thatit becomes the normal white type.

In order to evaluate the characteristics of those LCDs, the relationshipbetween the gate voltage and the transmittance of each of the LCDs ismeasured.

As a result, it is recognized that the gate OFF voltage can be decreasedby 2 volts, in case of the LCD which uses the color filter of thepresent invention, in comparison with the case of the LCD which uses theconventional color filter using Cr as the black matrix layer.

The reason for the above recognized fact, is estimated to be that, onone hand, in case of using the conventional color filter, a portion ofthe back light of the LCD is reflected by the black matrix layer surfaceto be an incident light to the TFT and become the cause of generating aphoto-electric current of the TFT, since the reflectance of the blackmatrix layer of the color filter is high, and, on the other hand, incase of using the color filter with the black matrix substrate of thepresent invention, the light emission amount to the TFT is reduced,since the reflectance of the black matrix layer surface is low,resulting in that the photo-electric current is reduced and the gate OFFvoltage is improved.

According to this result, the effect is confirmed in the LCD using thecolor filter with the black matrix substrate of the present invention,that the driving voltage of the LCD can be reduced, and thus the powerconsumption can be reduced. This is a very Good effect to make thecontinuous using time long, in case of driving a dry cell battery.

In order to evaluate another effect of the color filter of the presentinvention, the contrast ratio of the LCD is measured.

In the contrast ratio measurement at a bright environment, a contrastratio which is 2.4 times of the conventional color filter, can beobtained by using color filter of the present invention.

The reason for this is estimated to be that the influence of theexternal light is reduced because the reflectance of the black matrixlayer of the color filter is lowered.

In the contrast ratio measurement in a dark environment, a contrastratio which is 1.6 times the conventional color filter, can be obtainedby using the color filter of the present invention.

The reason for this is estimated to be that the photo-electric currentof the TFT is reduced as aforementioned, resulting in improvement of theleaking light at the time of displaying black.

As mentioned above, it can be recognized that the color filter of thepresent invention has the effect to reduce the power consumption of theLCD and improve the contrast ratio.

Experimental Example 3

As the transparent substrate, the 7059 glass made by Corning Co.(thickness=1.1 mm) is used, and the photo-sensitive resist, whichcomposition is listed below is coated on the transparent substrate, bythe spinner coating method (rotation speed=1500 r.p.m.). After that, itis dried under the condition that the temperature is 70° C. and thedrying time is 10 minutes, so that the photo-sensitive resist layer(thickness=0.6 μm) is formed.

Composition of the Photo-Sensitive Resist

polyvinyl alcohol 4.47% aqueous solution (Gohsenal T-330, made by NipponSynthetic Chemical Industry Co., Ltd.) . . . 1000 wt. parts

diazo resin 5% aqueous solution (D-011, made by Shinko Giken Co.) . . .57 wt. parts

With respect to this photo-sensitive resist layer, the light exposure isperformed through a photomask (line width=20 μm) for the black matrix. Asuper high pressure mercury lamp 2 kW, is used as the light source forthe light exposure, and the light is irradiated for 10 minutes. Afterthat, a spray development by use of water at room temperature isperformed, and air drying is performed, so that a relief image having aline width of 20 μm, for the black matrix, is formed.

Nextly, with respect to this transparent substrate, the heat treatmentprocess is applied by use of each temperature of 70°, 90°, 120°, 150°,170°, 190° C., respectively, for 30 minutes. After that, the transparentsubstrate is soaked in palladium chloride aqueous solution (Red Sumer,made by Kanigen Co.) for 30 minutes. Then, water washing and dewateringprocesses are applied to it, so that a relief including catalyst isobtained from the above mentioned relief image. The film thickness ofthe relief portion of the transparent substrate is 0.5 μm for all of thecases.

After that, the transparent substrate is soaked in nickel platingsolution including dimethyl amine borane as reducing agent (nickelplating solution Top Chemi Alloy B-1, made by Okuno Chemical IndustriesCo., Ltd.) for 4 minutes. Then, water washing and dewatering processesare applied to it, so that the black relief (black matrix) is formed(samples 1 to 6, respectively).

Nextly, with respect to each of those samples 1 to 6 produced asmentioned above, the X ray scattering intensity of the polyvinyl alcoholin the relief including catalyst before applying the electrolessplating, and the optical density of the black matrix after applying theelectroless plating process, are measured under the condition listedbelow.

The results of the measurements, are shown in Table 2.

X ray scattering intensity measurement

measuring method: X ray diffraction method device: RAD II-C (made byRigaku Co.)

specification: attachment . . . thin film attachment, scanning axis . .. 2θ, X ray incident angle . .. 0.5°, counting method . . . continuouscounting, sampling angle . . . 0.02° scanning speed . . . 1.0°/min,accumulated numbers . . . 3 times, target . . . Cu, lamp voltage . . .60 kV, lamp current . . . 300 mA, slit . . . DS 0.20 mm RS_(M) 0.80 mm,monochromater . . . used, counter . . . SC

optical density measurement

measuring method: spectroscopic transmittance measurement (wave length:400 to 700 nm)

device: microscope spectroscopic transmittance light measuring device(AH2-STK, made by Olympus Kogaku Kogyo Co.)

specification: spectroscopic wave length . . . 400 to 700 nm, wavelength resolution . . . 50 nm

As shown in Table 2, the samples 1 to 3, which X ray scatteringintensity values of the polyvinyl alcohol in the relief includingcatalyst, are within a range of 200 to 580 cps/μm, have high opticaldensities i.e. approximately not less than 3. However, the samples 4 to6, which X ray scattering intensity values are out of this range, do nothave sufficient optical densities. Here, the unit "cps/μm" means the Xray scattering intensity per unit film thickness of the relief imageportion.

As a whole, there is a tendency that, as the temperature of the heatprocess increases, the scattering intensity value increases, and at thesame time, the X ray diffraction peak angle is shifted to the higherangle side, and the width of half value thereof decreases. Namely,although it is a view of qualitative analysis, it is suggested that, asthe temperature of the heat process increases, the regulation of thelattice formed by the polymer chain of the polyvinyl alcohol in therelief image becomes shorter cycle, the degree of crystallizationincreases, and the dispersion rate of the orientation decreases.

As explained above in detail, a black matrix substrate can be providedby the present embodiment, which has a high dimensional accuracy, a highlight-shielding property, and a low reflectance, and which is suitableto form a color filter used for a color sensor, a flat display devicesuch as a liquid crystal display device, and an imager such as a CCD(Charge Coupled Device). Further, a color filter having a high contrastratio, and a liquid crystal display device having a good image quality,can also be provided by the present invention.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

                                      TABLE 1    __________________________________________________________________________                                 NICKEL PARTICLE                    REFLECTION   AVERAGE                    COEFFICIENT (%)                                 PARTICLE                                        5-50 nm                                             10-30 nm                                                  10-20 nm                                                       PHOTOGRAPHING              OPTICAL                    OBSERVOR                           FILM  DIAMETER                                        RANGE                                             RANGE                                                  RANGE                                                       DENSITY OF    SAMPLE    DENSITY                    SIDE   SURFACE                                 (nm)   (%)  (%)  (%)  PARTICLE    __________________________________________________________________________                                                       (%)    PRESENT   ≧3                    7.78   5.34  13.9   100  100  100  83.9    INVENTION    SAMPLE 1    PRESENT   ≧3                    10.04  15.43 18.4   100  100  63   85.4    INVENTION    SAMPLE 2    PRESENT   ≧3                    9.80   24.30 21.7   92   85   40   89.5    INVENTION    SAMPLE 3    PRESENT   1.83  4.89   5.15  15.2   100  100  82   62.1    INVENTION    SAMPLE 4    PRESENT   ≧3                    9.81   42.29 33.9   86   40   4    80.5    INVENTION    SAMPLE 5    COMPARISON              0.37  3.12   6.63  6.7    79   0    0    20.0    SAMPLE 1    COMPARISON              1.00  2.45   5.47  9.3    96   42   42   57.3    SAMPLE 2    COMPARISON              0.31  1.97   5.59  8.0    77   34   34   19.8    SAMPLE 3    COMPARISON              1.20  3.17   5.21  14.1   100  100  100  54.0    SAMPLE 4    __________________________________________________________________________

                                      TABLE 2    __________________________________________________________________________          TEMPERATURE              SCATTERING          OF HEAT    OPTICAL                           SCATTERING                                   STRENGTH                                           HALF VALUE    SAMPLE          TREATMENT (°C.)                     DENSITY                           ANGLE (2θ)                                   (cps/μm)                                           WIDTH (°)    __________________________________________________________________________    No. 1  70        3.3   19.25   226     4.07    No. 2  90        3.4   19.27   262     3.67    No. 3 120        2.9   19.39   576     1.94    No. 4 150        1.2   19.56   592     1.91    No. 5 170        0.0   19.52   976     1.54    No. 6 190        0.0   19.56   922     1.54    __________________________________________________________________________

What is claimed is:
 1. A black matrix substrate comprising:a substrate;and a black pattern formed on said substrate, said black patterncomprising a hydrophilic resin and metal particles precipitated therein;wherein (i) said metal particles have such a particle diameterdistribution that particles having particle diameter in a range of 10 nmto 20 nm are not less than 40% of the total particles, in a range of 10nm to 30 nm are not less than 80% of the total particles and in a rangeof 5 nm to 50 nm are not less than 90% of the total particles, (ii) aprojected area density at a conversion of 600 Å thickness of said metalparticles in said black pattern is not less than 60%, and (iii) anoptical density of said black matrix substrate is not less than 1.5;said black pattern being formed by depositing said hydrophilic resin onsaid substrate in the form of said black pattern, and subjecting theresin pattern to an electroless plating process to precipitate saidmetal particles in said black pattern.
 2. The black matrix substrate ofclaim 1, wherein said metal particles comprise at least one metalselected from the group consisting of Ni, Co, Fe, Cr, Cu, Pd, Au, Pt, Snand Zn.
 3. The black matrix substrate of claim 1, wherein the resinpattern comprises a catalytic component for the electroless platingprocess.
 4. The black matrix substrate of claim 1, wherein the resinpattern includes a catalytic component for the electroless platingprocess, and said metal particles are precipitated in said black patternvia a reducing agent which reduces said catalytic component in the resinpattern and metal ions in the electroless plating solution used in theelectroless plating process.
 5. The black matrix substrate of claim 4,wherein said reducing agent comprises one of a boron compound and aphosphoric compound.
 6. The black matrix substrate of claim 1, whereinthe resin pattern comprises polyvinyl alcohol, the X-ray scatteringintensity value of which is 200 to 580 cps/μm before formation of theblack pattern.
 7. The black matrix substrate of claim 1, wherein areflection coefficient of the black matrix substrate is less than 30% onboth the substrate side and the black pattern surface side.
 8. The blackmatrix substrate of claim 1, wherein said hydrophilic resin is ahydrophilic polyvinyl alcohol resin having a saponification value of 86to
 99. 9. The black matrix substrate of claim 1, wherein saidhydrophilic resin is a hydrophilic polyvinyl alcohol resin having anaverage degree of polymerization of 500 to
 1700. 10. The black matrixsubstrate of claim 1, wherein said hydrophilic resin is a hydrophilicpolyvinyl alcohol resin having a saponification value of 86 to 99 and anaverage degree of polymerization of 500 to 1700.